[Refactoring] Fix stack use after free in new async refactorings

Resolves rdar://73984220

Author: bnbarham

lib/IDE/Refactoring.cpp

@@ -5249,7 +5249,8 @@ bool RefactoringActionConvertCallToAsyncAlternative::performChange() {
   assert(CE &&
          "Should not run performChange when refactoring is not applicable");
 
-  AsyncConversionStringBuilder Builder(SM, DiagEngine, AsyncHandlerDesc());
+  AsyncHandlerDesc TempDesc;
+  AsyncConversionStringBuilder Builder(SM, DiagEngine, TempDesc);
   Builder.convertNode(CE);
 
   if (DiagEngine.hadAnyError())
@@ -5281,7 +5282,8 @@ bool RefactoringActionConvertToAsync::performChange() {
   assert(FD &&
          "Should not run performChange when refactoring is not applicable");
 
-  AsyncConversionStringBuilder Builder(SM, DiagEngine, AsyncHandlerDesc());
+  AsyncHandlerDesc TempDesc;
+  AsyncConversionStringBuilder Builder(SM, DiagEngine, TempDesc);
   Builder.convertFunction(FD);
 
   if (DiagEngine.hadAnyError())

test/refactoring/ConvertAsync/basic.swift

@@ -1,5 +1,3 @@
-// rdar://problem/73984220
-// XFAIL: asan
 enum CustomError: Error {
   case invalid
   case insecure

test/refactoring/ConvertAsync/convert_function.swift

@@ -1,5 +1,3 @@
-// rdar://problem/73984220
-// XFAIL: asan
 enum CustomError : Error {
   case Bad
 }

test/refactoring/ConvertAsync/convert_params_multi.swift

@@ -1,5 +1,3 @@
-// rdar://problem/73984220
-// XFAIL: asan
 func manyWithError(_ completion: (String?, Int?, Error?) -> Void) { }
 
 // RUN: %refactor -convert-call-to-async-alternative -dump-text -source-filename %s -pos=%(line+1):3 | %FileCheck -check-prefix=MANYBOUND %s

test/refactoring/ConvertAsync/convert_params_single.swift

@@ -1,5 +1,3 @@
-// rdar://problem/73984220
-// XFAIL: asan
 func withError(_ completion: (String?, Error?) -> Void) { }
 func test(_ str: String) -> Bool { return false }
 

test/refactoring/ConvertAsync/convert_result.swift

@@ -1,5 +1,3 @@
-// rdar://problem/73984220
-// XFAIL: asan
 func simple(_ completion: (Result<String, Error>) -> Void) { }
 func noError(_ completion: (Result<String, Never>) -> Void) { }
 func test(_ str: String) -> Bool { return false }

test/refactoring/ConvertAsync/errors.swift

@@ -1,5 +1,3 @@
-// rdar://problem/73984220
-// XFAIL: asan
 func simple(completion: (String?, Error?) -> Void) { }
 
 func mismatches() {